

A276786


a(1) = 1; subsequent terms are defined by the rule that if m is present so are 2m+1 and 3m+1; repeated terms are included; final list is sorted.


3



1, 3, 4, 7, 9, 10, 13, 15, 19, 21, 22, 27, 28, 31, 31, 39, 40, 43, 45, 46, 55, 57, 58, 63, 63, 64, 67, 79, 81, 82, 85, 87, 91, 93, 94, 94, 111, 115, 117, 118, 121, 127, 127, 129, 130, 135, 136, 139, 159, 163, 165, 166, 171, 172, 175, 175, 183, 187, 189, 189, 190, 190, 193, 202, 223, 231, 235, 237, 238
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OFFSET

1,2


COMMENTS

31 is the first number to appear twice. This is a multiset version of the KlarnerRado sequence A002977.
20479 is the first number to appear three times.  Rémy Sigrist, Dec 19 2016


REFERENCES

J. C. Lagarias, Erdos, Klarner and the 3x+1 Problem, Amer. Math. Monthly 123 (No. 8, 2016), 753776. See S# on page 756.


LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..29993 [Terms up to 500000]
Rémy Sigrist, C99 program for A276786


MAPLE

KR:=proc(lis) local i, j, t1, t2, t3;
t1:=lis; t2:=nops(lis); t3:=[];
for i from 1 to t2 do j:=t1[i];
t3:=[op(t3), 2*j+1, 3*j+1]; od: sort(t3); end;
t:=[1]; b:=[1];
for n from 1 to 10 do
t:=KR(t); b:=[op(b), op(t)]; b:=sort(b);
od: b;


CROSSREFS

Cf. A002977. See A276787 for repeated terms.
Sequence in context: A029739 A005098 A185661 * A002977 A024799 A240531
Adjacent sequences: A276783 A276784 A276785 * A276787 A276788 A276789


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Oct 06 2016


STATUS

approved



